Plastic frame assembly for bearing weight and method of assembly

ABSTRACT

A plastic frame assembly ( 10 ) for bearing weight and a method of assembling same, comprising a plastic support member ( 12 ) having a bottom portion ( 14 ) and a top portion ( 16 ). The bottom portion ( 14 ) has a channel ( 18 ), a plastic-affiliating migratory securing adhesive ( 20 ), and a flexible porous membrane ( 22 ). The plastic affiliating migratory securing adhesive ( 20 ) is applied to the channel ( 18 ) and the flexible porous membrane ( 22 ) is positioned on top of the channel ( 18 ) and forced into the channel ( 18 ). The plastic affiliating migratory securing adhesive ( 20 ) migrates through the flexible porous membrane ( 22 ) and secures the flexible porous membrane ( 22 ) to the bottom portion ( 14 ) of the plastic support member ( 12 ). The top portion ( 16 ) of the plastic support member ( 12 ) may register with the bottom portion ( 14 ) in such a way so that the flexible porous membrane ( 22 ) is held in place only by the plastic affiliating migratory securing adhesive ( 20 ).

FIELD OF THE INVENTION

This invention relates in general to frame assemblies and moreparticularly to a plastic frame assembly that can bear significantweights and a method of assembling the plastic frame assembly.

BACKGROUND OF THE INVENTION

Support or frame assemblies have typically been developed to be able tosupport significant amounts of weights as seen in their use for chairsand other forms of seating. In general these assemblies have tried toimprove the strength and the support of the seating so that the user ismore comfortable, while providing easier manufacture and assembly.

Prior art frame assemblies addressing the aforenoted issues include,U.S. Pat. No. 268,095 issued on Nov. 28, 1882 to Henry S. Hale. Thispatent relates a seat which consists substantially of a rectangularouter frame, in combination with a rectangular inner frame insubstantially the same plane and fitting closely inside thereof; and itconsists substantially in combining with two such frames one or moresupporting bars, preferably of metal.

Kwasnik et al. is the owner of U.S. Pat. No. 5,121,963, which issued onJun. 16, 1992 and relates to an upper periphery forming a U-shapedchannel. A fabric material is wrapped about the substrate having an edgedisposed within the U-shaped channel. The armrest assembly furtherincludes a U-shaped retainer ring for interlocking disposition in thechannel. The retainer ring includes gripping members for gripping thematerial as the retainer ring is forcibly inserted in the channel andfor retaining the material in the U-shaped channel. The retainer ringfurther includes co-acting members spaced laterally from the grippingmembers and further spaced from the edge of the material and including apair of longitudinal recesses for interlocking engagement with aplurality of hooks extending from the U-shaped channel to retain thering and material in the channel.

Seroldi is the owner of U.S. Pat. No. 5,645,321, which issued on Jul. 8,1997 relates to the framework which includes two lateral sections thateach have a protruding tongue, provided with fixing U-shaped elementsoriented surrounding the tongue. Each belt passes outside the U-shapedsections and is then folded up backwards and inserted between the tongueand the U-shaped element so that the tension exerted by the belt pressesthe U-shaped element in order to block the end of the belt against thetongue.

Although the prior art addresses some of the issues surrounding frameassemblies and the need for additional support and strength, the priorart devices still require some means to hold the seat or seat materialitself in place. Furthermore, prior art devices do not address a frameassembly that is entirely assembled out of plastic. Thus, a frameassembly that has additional strength while being manufacturedcompletely out of plastic, requires minimum parts to hold the seatmaterial in place and is easy to assemble with low cost is desirable.

SUMMARY OF THE INVENTION

An object of one aspect of the present invention is to provide animproved plastic frame assembly for bearing weight and a method ofassembling same.

In accordance with one aspect of the present invention there is provideda plastic frame assembly for bearing weight comprising a plastic supportmember having a bottom portion and a top portion. The bottom portion hasa channel, a plastic-affiliating migratory securing means, and aflexible porous membrane. The plastic affiliating migratory securingmeans is applied to the channel and the flexible porous membrane ispositioned on top of the channel and forced into the channel. Theplastic affiliating migratory securing means migrates through theflexible porous membrane and secures the flexible porous membrane to thebottom portion of the plastic support member. The top portion of theplastic support member may register with the bottom portion in such away so that the flexible porous membrane is held in place only by theplastic affiliating migratory securing means.

Conveniently, the plastic frame assembly may further comprise of aplastic setting member positioned within said channel on top of theflexible porous membrane to force the flexible, porous membrane into thechannel for securement to the bottom portion of the plastic supportmember.

In accordance with another aspect of the present invention there isprovided a method of assembling a plastic frame assembly for bearingweight comprising applying to the channel, the plastic affiliatingmigratory securing means. Positioning upside down on a top ram assemblythe plastic support member and securing it to the top ram assembly byspring pins. Positioning on a plate directly below the top ram assembly,a series of adjustable pins to match the contour of a plastic settingmember.

Securing the plastic setting member above the series of adjustable pinswith spring-loaded hooks and stretching the flexible porous membraneabove the plastic setting member. Moving the top ram assembly downwardlyso that the series of adjustable pins contact the plastic setting memberthereby releasing the spring-loaded hooks and forcing the plasticsetting member and the flexible porous membrane into the channel forcontact with the plastic affiliating migratory securing means. Releasingthe top ram assembly whereby the flexible porous membrane is adhered tothe plastic support member on the top ram assembly.

Advantages of the present invention include the ability for the plasticframe assembly to support significant amounts of weight using allplastic components; reducing the number of components or parts for theframe assembly to allow for easier and less costly assembly; use of theplastic frame assembly for chairs, benches, sofas, patio furniture,displays, signs, and in the automotive and aerospace environments, andan easier assembly method that allows for quick assembly with precisioncontouring of the frame while using only plastics.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of the preferred embodiments are provided hereinbelow by way of example only and with reference to the followingdrawings, in which:

FIG. 1 in an exploded view, illustrates a plastic frame assembly for aseat;

FIG. 2 in an exploded view, illustrates a plastic frame assembly for aback in accordance with a preferred embodiment of the present invention.

FIG. 3 in a cross-sectional view along the lines 3-3, illustrates thepreferred embodiment of FIG. 1 or 2 of the present invention.

FIG. 4 in a cross-sectional exploded view along the lines 4-4,illustrates the preferred embodiment of FIG. 1 or 2 of the presentinvention.

FIG. 5 in a perspective view, illustrates the assembly machine for thepresent invention.

FIG. 6 in a partial perspective view, illustrates the assembly machineof FIG. 5.

FIG. 7 in a partial perspective view, illustrates the series of pins ofthe assembly machine of FIG. 5.

FIG. 8 in a perspective view, illustrates the top ram assembly of theassembly machine.

In the drawings, preferred embodiments of the invention are illustratedby way of example. It is to be expressly understood that the descriptionand drawings are only for the purpose of illustration and as an aid tounderstanding, and are not intended as a definition of the limits of theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1, 2, 3 and 4, there is illustrated in exploded andcross-sectional views, a plastic frame assembly for bearing weight for achair seat and back respectively in accordance with a preferredembodiment of the present invention. The plastic frame assembly 10includes a plastic support member 12 having a bottom portion 14 and atop portion 16. The bottom portion 14 has a channel 18, aplastic-affiliating migratory securing means 20, and a flexible porousmembrane 22. The plastic affiliating migratory securing means 20 isapplied to the channel 18 and the flexible porous membrane 22 ispositioned on top of the channel 18 and forced into the channel 18. Theplastic affiliating migratory securing means 20 migrates through theflexible porous membrane 22 and secures the flexible porous membrane 22to the bottom portion 14 of the plastic support member 12.

The top portion 16 of the plastic support member 12 may register withthe bottom portion 14 in such a way so that the flexible porous membrane22 is held in place only by the plastic affiliating migratory securingmeans 20. Both the bottom portion 14 and the top portion 16 may be madefrom injection molded, ergonomically contoured Nylon 6/6, 15%-30% glassreinforced, depended on whether plastic support member is a back base orseat base for a chair or bench.

The plastic frame assembly 10 may further comprise of a plastic settingmember 24 positioned within the channel 18 on top of the flexible porousmembrane 22 to force the flexible, porous membrane 22 into the channel18 for securement to the bottom portion 14 of the plastic support member12. The plastic setting member 24 adheres to the flexible porousmembrane 22 as the plastic affiliating migratory securing means 20migrates through said flexible porous membrane 22 and contacts saidplastic setting member 24.

The plastic setting member 24 may be a flexible plastic spline 26 sizedto contour fit into the channel 18. The purpose of the flexible plasticspline 26 is to hold the flexible porous membrane 22 in place during theassembly of the plastic frame assembly 10. The flexible plastic spline26 is injection molded in a single piece from plastic such as Nylon 6/6or Nylon 6/6, 15% glass reinforced. The flexible plastic spline 26 maybe contoured to match the channel 18 of the bottom portion 14. Forexample if the plastic frame assembly 10 was constructed forergonomically designed chair back or seat, the channel 18 would bemolded into the bottom portion 14 of the plastic support member 12, andthe flexible plastic spline 26 would molded to match the contour of thechannel 18.

The flexible porous membrane 22 may be a plastic fabric such as wovenmesh polyester fabric 28 with the warp and the weft of differentconstruction and durometer rating. Specifically the warp of the fabric28 may be a polyester mono-fibre (55 durometer) while the weft may be apolyester multi-strand yarn (1000 denier).

The plastic-affiliating migratory securing means 20 may be a plasticadhesive, such as a two-part acrylic. The purpose of theplastic-affiliating migratory securing means 20 is to retain theflexible porous membrane 22 within the channel 18. Therefore the onlyelement that holds the flexible porous membrane 22 to the plasticsupport member 12 and allows for weight bearing on the flexible porousmembrane 22 is the plastic-affiliating migratory securing means 20.

Referring to FIGS. 5-8, in accordance with another aspect of the presentinvention there is provided a method of assembling a plastic frameassembly. 10 for bearing weight. The method of assembling a plasticframe assembly 10 includes applying to the channel 18, the plasticaffiliating migratory securing means 20. The plastic support member 12is positioned upside down on a top ram assembly 30 and is secured to thetop ram assembly 30 by spring pins 32. Therefore the channel 18 isfacing downwards. The top ram assembly 30 is a vertical ram actuated byan air cylinder. The top ram assembly 30 may develop up to 10,000 poundsof force.

A base plate 34 is positioned directly below the top ram assembly 30 andhas a series of adjustable pins 36 arranged in a single row so as tomatch the contour of the plastic setting member 24. The base plate 34may have for example 65 pins for a chair seat and 76 pins for a chairback. The heads of the adjustable pins 36 are contoured to fit and guidethe contour of the plastic setting member 24. The plastic setting member24 is secured above the adjustable pins 36 by spring-loaded hooks 38.

The flexible porous membrane 22 is stretched above the plastic settingmember 24. In general the flexible porous membrane is pre-stretched bymeans of four clamping assemblies spaced 90° apart. The clampingassemblies may include a clamp plate mounted on a linear slide and aseries of cylinders. A cylinder activates the clamp plate to grip theflexible porous membrane 22 while another cylinder stretches theflexible porous membrane 22 to the desired tension. The flexible porousmembrane 22 may be stretched to different tension requirements in onedirection or the other.

The top ram assembly 30 moves downwardly so that the series ofadjustable pins 36 contact the plastic setting member 24 therebyreleasing the spring-loaded hooks 38 and forcing the plastic settingmember 24 and the flexible porous membrane 22 into the channel 18 forcontact with the plastic affiliating migratory securing means 20.Specifically the top ram assembly 30 presses down on the plastic settingmember 24 and the flexible porous membrane 22 with approximately 6000pounds of force.

The flexible porous membrane 22 is trimmed by a hot knife assembly,namely a 22 gauge stainless steel blade coated with a Teflon (Registeredtrademark) based Endura (Registered trademark) material. The blade isformed to the contour of plastic support member 12 and may have heatersapplied to it to elevate the temperature of the blade to 500° F. Priorto the trimming of the flexible porous membrane 22, the clamps arereleased thereby allowing the hot knife assembly to trim the flexibleporous membrane 22.

The top ram assembly 30 and specifically the cylinder then releaseswhereby the flexible porous membrane 22 is adhered to the plasticsupport member 12 on the top ram assembly 30.

Other variations and modifications of the invention are possible. Allsuch modifications or variations are believed to be within the sphereand scope of the invention as defined by the claims appended hereto.

1. A plastic frame assembly for bearing weight comprising: a) a plasticsupport member having a bottom portion and a top portion; said bottomportion having a channel; b) a plastic-affiliating migratory securingmeans; and c) a flexible porous membrane; wherein said plasticaffiliating migratory securing means is applied to said channel and saidflexible porous membrane is positioned on top of said channel and forcedinto said channel whereby said plastic affiliating migratory securingmeans migrates through said flexible porous membrane and secures saidflexible porous membrane to said bottom portion of said plastic supportmember; said top portion of said plastic support member registering withsaid bottom portion in such a way so that said flexible porous membraneis held in place only by said plastic affiliating migratory securingmeans.
 2. A plastic frame assembly for bearing weight as claimed inclaim 1 further comprising a plastic setting member wherein said plasticsetting member is positioned within said channel on top of said flexibleporous membrane to force said flexible, porous membrane into saidchannel for securement to said bottom portion of said plastic supportmember.
 3. A plastic frame assembly for bearing weight as claimed inclaim 2 wherein said plastic setting member adheres to said flexibleporous membrane as said plastic-affiliating migratory securing meansmigrates through said flexible porous membrane and contacts said plasticsetting member.
 4. A plastic frame assembly for bearing weight asclaimed in claim 2 wherein said plastic setting member is a flexibleplastic spline sized to contour fit into said channel.
 5. A plasticframe assembly for bearing weight as claimed in claim 2 wherein saidflexible porous membrane is a plastic fabric.
 6. A plastic frameassembly for bearing weight as claimed in claim 5 wherein said plasticfabric is a woven mesh polyester fabric.
 7. A plastic frame assembly forbearing weight as claimed in claim 2 wherein said plastic-affiliatingmigratory securing means is a plastic, two-part adhesive.
 8. A plasticframe assembly for bearing weight as claimed in claim 2 wherein saidplastic frame assembly is applied to a chair.
 9. A plastic frameassembly for bearing weight as claimed in claim 2 wherein said plasticframe assembly is applied to a bench or couch.
 10. A method forassembling a plastic frame assembly for bearing weight, said plasticframe assembly having a plastic support member having a channel; aplastic-affiliating migratory securing means; and a flexible porousmembrane and a plastic setting member, comprising: (a) applying to saidchannel, said plastic affiliating migratory securing means; (b)positioning upside down on a top ram assembly said plastic supportmember, said plastic support member secured to said top ram assembly byspring pins; (c) positioning on a plate a series of adjustable pins tomatch the contour of said plastic support member, said plate positioneddirectly below said top ram assembly; (d) securing said plastic settingmember above said adjustable pins by spring-loaded hooks; (e) stretchingsaid flexible porous membrane above said plastic setting member; (f)moving said top ram assembly downwardly wherein said series ofadjustable pins contact said plastic setting member releasing saidspring-loaded hooks, said series of adjustable pins forcing said plasticsetting member and said flexible porous membrane into said channel forcontact with said plastic affiliating migratory securing means in saidchannel of said plastic support member; (g) releasing said top ramassembly whereby said flexible porous membrane is adhered to saidplastic support member on said top ram assembly.
 11. A method forassembling a plastic frame assembly for bearing weight as claimed inclaim 10 further comprising stretching said flexible porous membrane toa preferred tension by a series of clamps.
 12. A method for assembling aplastic frame assembly for bearing weight as claimed in claim 11 furthercomprising releasing said clamps and trimming said flexible porousmembrane to a desired size.
 13. A method for assembling a plastic frameassembly for bearing weight as claimed in claim 12 wherein said seriesof adjustable pins are a single row of pins having contoured heads toregister with the contoured shape of said plastic setting member.
 14. Amethod for assembling a plastic frame assembly for bearing weight asclaimed in claim 13 wherein said pins maintain and control the movementof said plastic setting member into said channel and aid in maintainingsaid shape of said plastic setting member.
 15. A method for assembling aplastic frame assembly for bearing weight as claimed in claim 14 whereinsaid pins hold and position said flexible porous membrane within saidchannel for a maximum of two minutes to allow for saidplastic-affiliating migratory securing means to migrate through saidflexible porous membrane to secure said flexible porous membrane to saidplastic support member.
 16. A method for assembling a plastic frameassembly for bearing weight as claimed in claim 10 wherein said plasticsupport member further comprises a bottom portion and a top portionwherein said bottom portion has said channel.
 17. A method forassembling a plastic frame assembly for bearing weight as claimed inclaim 16 wherein said top portion of said plastic support memberregisters with said bottom portion in such a way so that said flexibleporous membrane is held in place only by said plastic affiliatingmigratory securing means.
 18. A method for assembling a plastic frameassembly for bearing weight as claimed in claim 17 wherein said top ramapplies sufficient pressure to said plate to ensure said flexible porousmembrane is forced into said channel.
 19. A method for assembling aplastic frame assembly for bearing weight as claimed in claim 18 appliedto a chair.
 20. A method for assembling a plastic frame assembly forbearing weight as claimed in claim 18 applied to a bench or sofa.